Alpha drive ratio

A

Archnawan

Seaman Apprentice
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Apr 26, 2005
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I have an Alpha One, Gen 2 and need to find the drive ratio. The only stamp I see is DL00075 on the upper unit. Can I determine the ratio without disassembly? If not what do I have to remove to find out?<br /><br />Motor is a 5.0L, and I'm am considering replacing outdrive with one that is 1.62 ratio but want to make sure the gearing is appropriate.
 
Bondo

Bondo

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Re: Alpha drive ratio

You Should have a 1.5/1......<br /><br />A 1.62/1 would need about 2" Bigger Prop to make up the Difference...........
 
A

Archnawan

Seaman Apprentice
Joined
Apr 26, 2005
Messages
31
Re: Alpha drive ratio

Hmm, so if I have a 15" I would need a 17" to keep the same top rpm?<br /><br />If so that could be a good thing. The unit is on a 26 foot bayliner that I have always felt is a little underpowered. With a 15" stainless it tops at about 4400 rpm so if I leave the same prop on and top at 4600 to 4700,(still in spec?), it should give me better overall performance, right?
 
achris

achris

More fish than mountain goat
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May 19, 2004
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27,468
Re: Alpha drive ratio

Originally posted by Cap'n Aye:<br /> Hmm, so if I have a 15" I would need a 17" to keep the same top rpm?<br /><br />If so that could be a good thing. The unit is on a 26 foot bayliner that I have always felt is a little underpowered. With a 15" stainless it tops at about 4400 rpm so if I leave the same prop on and top at 4600 to 4700,(still in spec?), it should give me better overall performance, right?
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yes.<br /><br />Some 5.0l did come from the factory with 1.62:1. The only way to know for sure it to remove the top cover and count the teeth, or turn the input shaft /yoke and count the revolutions of the prop shaft.<br /><br />Chris.........
 
Bondo

Bondo

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Re: Alpha drive ratio

Ohhh,.... On that Big of a boat,.. You just Might have a 1.65/1.......<br /><br />If that's the case,.... Going to the 1.84/1 would give you the 2"s of breathing room on your prop pitches...........<br /><br />I'd be Tempted to go with the 1.98/1s............<br />That Should put you into a 21" prop.............If you've got the 1.5/1 Now........
 
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